Sound printing mechanism



March 26, 1940. H, w, DUDLEY 2,195,081

SOUND PRINTING'` MECHANISM March 26, 1940- v H. w. DUDLEY 2,195,081

SOUND PRINTING MECHANISM Filed Jul,r 1 1938 5 Sheets-Sheet 2 March-ze,1940. H. w. ppDLY 12,195,081

SOUND PRINTING MECHANISH Filed July 1, 1938 5 Sheets-Sheet 3 NON-REPE4TBARS F/G. 4

76T 76E 74ss 76 76H /M/ENTOR By H W DUDL E Y aejouu/ L W- l PULL -BARSATTORNEY SOUND PRINT ING MECHANI SM n Filed'Ju1y- 1. 1938 5 Sheets-Sheet4 52 54 /NVEN TOR o By W DUDL EV 63 new A T TORNEV F Patented Mar. 26,1940 UNITED STATES PATENT OFFICE SOUND PRINTING MECHANISM Homer W.Dudley, Garden City, N. Y., assigner to Bell Telephone Laboratories,Incorporated, New York, N. Y., a corporation of New York ApplicationJuly 1, 1938, Serial No. 216,943

25 Claims.

This invention relates to sound printing mechanisms and has for anobject the provision of means for translating spoken sounds into printedWords.

In order that'a suitable printing mechanism may be controlled to typecharacters from which the spoken sounds may be interpreted by the eye,it is necessary to analyze the sounds and derive therefrom a set ofparameters which collectively dene each sound and distinguish each soundof importance in speech from all other speech sounds. In choosing theset of parameters to be employed for this purpose use is made of thefact that one set of parameters can be substituted for another setwithout any loss of denition so long as the number of independentparameters remains unchanged.

As pointed out in my earlier U. S. patent application Serial No.181,275, led December 23, 1937, the number of movable or variableyelements of the vocal system that are controlled as parameters to givethe desired speech production and are movable or variable substantiallyindependently of one another by the muscles of the vocal system issmall. In other words, the number of variables or parameters that canbecontrolled substantially independently in speech production is small,being of the order of ten. Moreover, for each of the physical elementsthe minimum time it can go through a complete cycle of change inposition is not less than about-.1- sec-' ond. Consequently, eachindependent variable has a fundamental frequency of not -over 10 cyclesper second while engaged in speechv production.

Therefore, the speech defining signals into which the spoken message istranslated for controlling the printing mechanism may be any signalsderived from the message providing the derived signals give as manyindependent variable quantities or parameters as the number ofindependent variables involved in the production of speech. Furthermore,the chosen parameters need not be entirelyeindependent provided theirnumber be increased suiiiciently to make up for their lack ofindependence. In accordance with the preferred form of this invention,the chosen parameters may be the average amounts of power present inselected subbands of the speech frequency range. For example, the speechfrequency range by means of band-pass lters may be divided into tensubbands collectively extending over the frequency range of importancein speech and the average amount of power in each subband may beselectively utilized to cause the printing of symbols representing themessage. The printed record will, of course, be phonetic in character ascontrasted with the usual printed record which is non-phonetic.

The printing mechanism employed in this in- 5 vention may comprise'aplurality of slotted code bars each controlled in its movement by theaverage amount of power in one of the subbands into which the speechwave is divided so that each slotted bar is capable of assuming any onelo of several positions dependent upon the power level in its assignedsubband' for each spoken sound. It, therefore, follows that the slottedbars in response to a spoken sound will assume relative positionsindividual to that sound and means testing for the relative actuatedpositions of the slotted bars may be utilized to control the printing ofa symbol indicative of that sound.

In accordance with a preferred embodiment of the sound printingmechanism of this invention 20 the speech sounds are picked up by amicrophone and transmitted to an amplifier whose gain is automaticallyadjusted for a constant speech level Without, however, disturbing therelative nloudness of the sounds making up a givenword. The relativelyconstant volume output of this amplifier is next analyzed by amultiplicity of band-pass filters each passing a different subband ofthe speech frequency range and collectively passing the importantfrequency range of 30 speech sound, for example, from 0 to 7500 cycles.The output of each filter then goes to a rectifier to produce a syllabicchange in current proportional to the amount of energy in the particularfrequency band passed by its filter. This syllabic changing energy fromeach rectifier energizes an electromagnet for actuating a selecting barwhich may be, similar in character to the code bars employed inteletypewriters. These selecting bars, therefore, have deflectionsvarying with the amount of energy in the particular subbands. Theselecting bars may have slots cut in them in such a manner that thespeech currents for a given sound line up one set of slots in the barsso that a testing device for that particular sound can fall into thealigned slots. When a testing device enters the slots, an associatedtyping key may be actuated to type on a movable recording tape a symbolrepresenting the given sound. Other features of the invention willappear from the detailed description hereinafter given.

Referring to the drawings,

Fig. 1 represents the electrical circuits of one form of this invention;

Fig. 2 represents printing mechanism which may be controlled by theelectrical apparatus of Fig. 1;

Fig. 3 represents the type of record obtainable by the apparatus ofFigs. 1 and 2;

Fig. 4 is a plan view of portions of the slotted bars utilized in theprinting apparatus of Fig. 2;

Figs. 5 to 10, inclusive, represent the various stages in the operationof a given type bar and its associated mechanism when controlled by theapparatus of Figs. 1 and 2;

Figs. ll-A to ll-D, inclusive, illustrate in schematic form how a typebar bearing a symbol representing a voiced stop sound may be preventedfrom printing when the analyzed sound is of a different type;

Figs. 12F-A to 12-D, inclusive, illustrate in schematic form how a typebar representing a voiced non-stop sound may be prevented from printingwhen the analyzed sound is of another type;

Figs. 13-A to 13-D, inclusive, illustrate in schematic form how a typebar bearing a symbol representing an unvoiced stop sound may beprevented from printing when the analyzed sound is of another type; and

Figs. 11-A to 14e-D, inclusive, illustrate in schematic form how a typebar bearing a symbol representing an unvoioed non-stop sound may beprevented from printing when the analyzed sound is of another type.

Before discussing the character of the apparatus illustrated in thedrawings, it is desirable to list the minimum number of symbols orcharacters which will be required to print phonetic speech. For thepurpose of this specication, the speech sounds are divided into fourgroups, namely, voiced stop sounds, voiced non-stop sounds, unvoioedstop sounds and unvoioed nonstop, sounds.

The voiced stop sounds of the rst group are three in number andcorrespond to the three sounds which in the English language aredesignated by the letters B, D and G.

The voiced non-stop sounds of the second group comprise twenty-foursounds which may be divided into thirteen vowels, ve semi-vowels, fourvoiced fricatives and two transitionals. The thirteen vowel sounds aregiven below by key Words rather than by phonetic symbols, with the vowelsounds in boldface type:

see fat omit fill chaotic tall well cool father ask book fur 'I'he fivesemi-vowels included in the second group are the consonants shown inboldface type of the following words:

man lit ring.

The four voiced fricatives are the portions of the following words inboldface type:

zeal azure vat then.

The two transitionals included in the second group are the w sound inwile and the y sound in you.

The third group, namely, the unvoiced stop sounds, comprise three soundsrepresented in the English language by the three letters P, T and K.

'Ihe fourth group, namely, the unvoioed nonstop sounds comprises a totalof six sounds including two unvoioed transitionals, the h sound in here,and the wh sound in what; and four unvoioed fricatives as indicated bythe consonants which are in boldface type, in the following Words:

seal ash fat thin.

This makes a minimum total of thirty-six phonetic symbols for recordingspeech sounds. Certain common sounds have been omitted from this listsince they may be represented by symbols already given. Thus the .isound in judge may be represented in print by two symbols, namely, bythe symbol representing the d sound followed by the symbol representingthe z sound in azure. The ch sound in church would be represented by twosymbols, namely, the symbol representing the t sound followed by thesymbol representing the sh sound of she. Similarly, all the voweldiphthongs have been considered as the combinations of two vowel sounds.

It is, therefore, contemplated that a minimum number of thirty-sixphonetic symbols will be needed in the printing mechanism to giveintelligible printed phonetic speech, but, of course, this number may beconsiderably enlarged as desired to provide additional symbolsrepresenting still other sounds customarily found in the Englishlanguage. The symbols employed on the type bars of the printingmechanism are preferably those of the alphabet of the InternationalPhonetie Association as given, for example, in Websters NewInternational Dictionary, published in 1934, or as given in a book ofMulgrave entitled Speech for the Classroom Teacher published in New Yorkin 1936 by Prentice-Hall, Incorporated.

Referring now t0 the circuit diaphragm of Fig. 1 the speech to beprinted may be picked up by a microphone 2U. In order to compensate forvariations in the volume of the received sounds so that the analyzedspeech currentsl will always be the equivalent of those produced by aperson talking with substantially the same degree of loudness and tocompensate for any intermediate telephone line between the point ofspeech pickup and the point of speech printing, the speech currentsreceived from microphone 20 are impressed upon an amplier 2| of the typecalled a vogad in the communication art, and shown in detail, forexample, in British Patent 381,831. That is, amplier 2| has its' gainautomatically controlled by slow variations in the level of the receivedcurrents but with its gain unchanged by syllabic variations in thereceived volume whereby the output ofamplier 2| gives the speechcurrents for each word at substantially the same level. In addition tothe vogad' or as a substitute for it, an instantaneous speech controlsuch as a compressor or expandor may be found useful in some cases, theformer to'reduce the operating range needed for adequate speechanalysis, the latter to reduce the elect of noise. A particular circuitfor the compressor is given in Crisson U. S. Patent No. 1,737,830 ofDecember 3, 1929, and for the expandor is given in the Mathes U. S.Patent 1,757,729 of May 6, 1930. At this point in the circuit of Fig. 1it is important to distinguish between currents representing voicedsounds and unvoioed sounds andthere fore, a portion of the output ofvogad 2| by leads 22 is impressed upon a fundamental frequencydiscriminating circuit 23 of such a character that the output currentfrom low-pass filter 24 Will be substantially zero for all unvoicedsounds but for voiced sounds will have an amplitude proportional to thepitch of the fundamental frequency. Hence, relay 25 which by leads 26 isconnected to the output-of lter 24 will be non-operated by unvoicedsounds but will be operated by all voiced sounds.

Therefore, for unvoiced sounds the output from the additional amplifier21 because of the non-operation of relay 25 will be impressed directlyupon ten band-pass filters F1 to F10 all connected in parallel to theoutput of amplifier 21. These band-pass filters collectively pass thefrequency range of importance in speech, say, from to 7500 cycles, withfilter F1 passing the band from 0 to 225 cycles per second; filter F2passing the band from 225 to 450 cycles per second; lter F3 passing theband from 450 to 700 cycles per second; filter F1 passing the band from700 to 1000 cycles per second; filter F5 passing the band from 1000 to1400 cycles per second; filter F0 passing the band from 1400 to 2000cycles per second; filter F7 passing the band from 2000 to 2700 cyclesper second; filter Fa passing the band from 2700 to 3800 cycles persecond; :filter F0 passing the band from 3800 to 5400 cycles per second;and filter F passing the band from 5400 to 7500 cycles per second. Theoutput from each of the band-pass filters F1 to F10 is rectified by oneof the rectiers D1 to D10 and the rectified current from each subband isimpressed upon one of the electromagnets R1 to R10. Therefore, eachelectroma'gnet R1 to R10 attracts its arma.- ture with a forcedetermined by the average energy level of that portion of the speechWave transmitted by its associated filter so that electromagnet R1attracts its armature with a pull determined by the average energy levelin the frequency range from 0 to 225 cycles per second, electromagnet R2attracts its armature with a pull determined by the average energy levelin the frequency range from 225 to 450 cycles per second, etc.

The armature of each of the electromagnets R1 to R10 is suitably coupledby a multiplying lever to one of the arcuate-shaped code bars B1 to B10shown more clearly in Fig. 2. Each code bar B1 to B10 is biased by meansof one of the springs 40 to a normal position whereby the left end of aslot 28 in each code bar lies against a stop pin 29. Hence, each of thecode bars B1 to B10 by means of its associated electromagnet will bemoved from its normal position an amount controlled at each instant bythe average energy level in the speech frequency subband passed by thefilter associated with each electromagnet. We may assume, for example,for the complex electrical wave representing a certain unvoiced soundsuch as s in sin that there is no appreciable energy lying in thefrequency band between 0 and 1400 cycles per second, and hence for sucha Wave code bars B1 to B5, inclusive, will remain in their normalpositions; that there is a small amount of energy in the band from 1400to 2000 cycles per second, and hence code bar B6 will be moved a smallamount; that there is a somewhat greater amount of energy in the bandfrom 2000 to 2700 cycles per second so that code bar Bv will be moved agreater distance than code bar B0; that there is slightly more energy inthe band from 2700 to 3800 cycles per second so that code bar B8 will bemoved a greater distance than code bar B1; that the amount of energy inthe band from 3800 to 5400 cycles per second is substantially greaterthan in the band from 2700 to 3800 cycles per second so that code bar B0will be moved considerably more than code bar B0; and that there issubstantially the same amount of energy in the band from 5400 to 7500cycles per second so that code bar B10 will be moved the same amount asB9. With the code bars occupying the positions just recited, they are insuch positions that when they are tested by the printing mechanism thecode bars will permit the printing of the symbol representing the ssound in sin but will not permit the printing of any other symbol. Themanner in which the testing of the code bars and the printing is donewill be described later.

The above description has traced the operation of the code bars inresponse to an unvoiced sound. Their operation for a voiced sound isquite similar except that for a voiced sound relay 25 will be operatedso that the output of amplifier 21 instead of being impressed directlyupon the band-pass filters will be transmitted through an equalizingnetwork 30 and another amplifier 3| before reaching the filters.Equalizer 30 is designed to correct the natural falling off of the upperharmonics with frequency in the case of sounds produced by the vocalcords and to make the amplitude of the fundamental and all its harmonicsmore nearly uniform as is the case with unvoiced sounds. The amount ofequalization needed can be obtained from Fig. 2 of my above-mentionedapplication Serial No. 181,275 from which it is apparent that therequired equalization varies from a loss of decibels at 100 cycles persecond to zero at 3000 cycles per second; and that for frequencies above3000 cycles per second a gain is needed foi' the equalizer instead of aloss. However, such a gain would lead to increasing the line noise byamplication, so from 3000 cycles to the upper end of the speech band itis more desirable to have zero loss and such a condition may be assumedfor the circuits of Fig. 1 herein. This equalization produced by network30 makes each subband of the speech frequency range equally useful indetermining what voiced symbols shall be printed as otherwise signicantamounts of energy in certain of the upper subbands might be at such asmall energy level compared to the fundamental that the code bar forsuch an upper subband might be left in normal position and cause falseprinting. Equalizer 30, therefore, reduces the amplitude of thefundamental and the major harmonics to a level more nearly equal to thehigher harmonics and then amplifier 3| is employed to raise the level ofthe fundamental and its harmonics to the level desired to secure theselective operation of the code bars.

It may be found helpful to insert an equalizer 4| after amplifier 21 tocorrect for the increasing amounts of energy in the upper bands ascompared with the lower bands passed by filters F1 to F10 due to theincreasing Width of the passed band as one proceeds from filter F2 tofilter F10; for example, filters F1 and F2 pass bands 225 cycles inwidth while lter F10 passes a band 2100 cycles wide. This correctionproduced by equalizer 4| may amount to a loss of 1 decibel per channelstarting with the channel containing filter F2.

As additional aids in preventing false printing, applicant in thepreferred embodiment of the invention employs a so-called Voicing lockwhich must be operated before a symbol for a voiced sound may be printedand also employs a stop consonant lock which must be operated before asymbol for a stop consonant may be printed. The voicing lock comprisesan electromagnet 32 connected to the output of filter 24 and aspreviously described the output current of filter 24 is substantiallyzero for unvoiced sounds while its output is of substantial amplitudefor all voiced sounds. Hence, electromagnet 32 will be energized onlyfor voiced sounds.

Connected across the output of vogad 2| in parallel with channel 23 isanother channel 33 leading to an electromagnet 34 constituting a part ofthe stop consonant lock of the printing mechanism. Channel 33 includesan amplifier 35 to isolate channel 33 from the other circuits connectedacross the output terminals of vogad 2|. The output of amplifier 35 isrectified by rectifier 36 and then impressed on the low-pass filter 31which passes the band between and 80 cycles to eliminate the fundamentalfrequency of any voiced sound and the conductors between filter 31 andthe input of low frequency amplifier 38 are shunted by a largeinductance 39 with elect-romagnet 34 responsive to the output ofamplifier 38. When a sudden change in the energy level such as caused bya stop consonant sound is received by channel 33 a sudden pulse ofenergy goes through circuit 33 and builds up a potential acrossinductance 39 which being amplified by amplifier 38 will causeelectromagnet 34 to operate. However, the sustained average energylevelof a voiced sound will not produce sufcient potential acrossinductance 39 to cause the operation of electromagnet 34. The manner inwhich electromagnets 32 and 34 control the printing operation will bedescribed later.

Referring now to Fig. 2 it will be seen that the code bars B1 to B10 arearcuate-shaped and mounted one above the other in a suitable manner toenable each code bar to move along an arcuate path when its associatedelectromagnet R1 to R10 is energized, each code bar being biased by aspring 40 to a normal position with the left end of slot 28 against stoppin 29, and the maximum movement of any code bar determined by thelength of slot 28.

These code bars B1 to B10 and certain parts of the associated apparatusare somewhat similar to teletypewrter apparatus as disclosed in Lang etal. U. S. Patent 2,106,805, issued February l, 1938, or Morton et al. U.S. Patent 1,745,633, issued February 4, 1930, except that the code barsof a teletypewriter are fewer in number and occupy only two possiblepositions, an operate position and a non-operate position, While eachcode bar B1 to B10 is designed to be advanced over a wide range ofpositions including not only its normal position and its maximumposition but also any intermediate position. That is, in order to printa given symbol it may be necessary that one code bar be moved .3 of thedistance between its normal position and maximum position, another codebar .4 of that distance, another code bar .'7 of that distance, anothercode bar to maximum position, etc. The arrangements of the slots in thecode bars B1 to B10 will be described later.

In order to render the printing mechanism of Fig. 2 effective, switch 5lshould first be closed to connect a suitable power supply to motor 52 torotate gear 53 which in turn rotates the drive shaft 54. Switch 55 maythen be closed to operate relay 56, thereby bringing into contact theparts of clutch 51. This rotates cam 58 which forces lever 59 back andforth thereby causing the main bail plunger 6! to move up and down andcause the main bail 6l to execute a similar upward and downwardmovement. Each upward movement of main bail 6I causes all pull bars 50to test the setting of the code bars B1 to B10, there being a pull bar58 for each character to be printed although for simplification purposesonly one pull bar is completely shown on the drawings.

As shown more clearly in Fig. each type bar 62 is suitably supported forrotative movement about an axis defined by a stationary pin 63. Thelower end of each type bar forms a segmental gear 64 which meshes with atoothed rack 65 forming the lower end of each pull bar 50, suitablemeans, not shown, being provided for holding gear segment 64 inengagement with rack 65, while permitting a slight pivotal movement ofthe associated pull bar 5U. Each pull bar 50 above rack 65 extends firstslightly outwardly and then upwardly and a spring 66 tends to move thepull bar downwardly and rearwardly and hold the pull bar and itsassociated type bar in normal position as shown in Fig. 5 with the pullbar pressed against the forward edge of the main bail 6I when the mainbail is in its normal position. It will also be noted from Fig. 5 thatwith the pull bars in normal position an intermediate portion 68 of eachpull bar lies in front of but is spaced slightly from the notched inneredges of the code bars B1 to B10.

Main bail 6| as previously described is continually being raised andlowered by plunger 60. As bail 6| starts to move upwardly as in Fig. 6this upward movement due to cam surface 69 on each pull bar enablessprings 66 to move all pull bars 59 rearwardly against the notched frontedges of the code bars B1 to B10 as shown in Fig. 6. It may be assumedthat electromagnets R1 to R10 have moved code bars B1 to B10 to suchpositions as to permit one of the pull bars 50 to drop into the slots(see Fig. '7) far enough to bring a rearwardly projecting lug into thepath of movement of the main bail 6|. Upon the continued upward movementof main bail 6I its forward edge engages lug 10 of the selected pull barand moves the selected pull bar upwardly (see Fig. 8) thereby throwingthe associated type bar 62 to the printing point, thereby printing asymbol on a strip of paper supported by platen 1|. The latter part ofthe upward movement of the selected pull bar causes lug 10 to engage astationary cam 12 which throws the selected pull bar forwardly and outof the notches in the code bars as shown in Fig. 9 whereby the code barsmay be reactuated for another alignment to provide for the laterselection of another pull bar. Spring 66 thereupon lowers the selectedpull bar and raises its associated type bar to substantially theirnormal positions as shown in Fig. 10 in which the bail bar Bl is shownas returned to its starting position.

Inasmuch as it is contemplated that occasionally the frequency ofmovement .of the main bail 6I may cause its next upward excursion beforethe code bars have been moved from the align ment which permitted theactuation of a type bar by its previous excursion, the preferred form ofthe invention provides a repetition lock whereby after one pull bar hasentered the slots in the code bars the said one pull bar cannot reenterthe slots until there has been a realignment of at least one of the codebars. Associated with each pull bar 50 is a non-repeat lock bar 16pivoted on a stationary pin 11. The upper portion 19 of bar 16 is biasedtowards the rear edges of the code bars due to biasing springs 18. Therear edges of the code bars B1 to B10 are also provided with shallowslots as will be described later so arranged that when the code barsoccupy positions to enable a selected pull bar to enter slots in thefront edges of the code bars all the code bars will have aligned slotsin their rear edges to permit the entrance of the non-repeat barassociated with the particular pull bar. However, as long as each pullbar 58 is in its normal position as in Fig. the associated non-repeatbar 16 is prevented from entering any slots in the code bars since thereis pivoted to the lower end of each pull bar 58 a spring latch 88engaging a hook 8| on the lower end of the non-repeat bar 16.

As soon as any pull bar 50 after entering the aligned slots in the frontedges of the code bars has been pulled upwardly due to the main bail 6|engaging lug '|8 (Fig. 8) the latch 80 is lifted free of hook 8| andspring 18 then causes the associated non-repeat bar to enter the alignedslots in the rear edges of the code bars. Pivoted to the upper end ofeach non-repeat bar 16 is an angular lever 82 biased by spring 83 to theposition shown in Fig. 5 with its arm 84 extending towards but notcontacting with the associated pull bar 58 as long as the pull bar andthe nonrepeat bar are in their normal positions of Fig. 5.

When the initial movement of the main bail 6| has permitted a pull barto enter the aligned slots in the code bars this rearward movement ofsuch a pull bar allows arm 84 to ride on the upper surface of lug 85 asshown in Fig. '7. When any pull bar 50 is lifted upwardly to cause aprinting operation (Figs. 8 and 9) lug 85 passes above arm 84 and sincethe associated non-repeat bar 16 is now allowed to enter the alignedslots in the rear edges of the code bars the subsequent lowering of thepull bar 58 after the printing operation as in Fig. 10 causes arm 84 tobe caught by lug 85 as long as the non-repeat bar 16 lies in the slotson the code bars. Arm 84, therefore, prevents the pull bar 58 fromentering the slots in the front edges of the code bars a second time aslong as its associated non-repeat bar 16 is lying in the aligned slotsin the rear edges of the code bars. It will also be noted from Fig. 10that with the pull bar 58 retracted after a printing operation and withthe associated non-repeat bar 16 lying in the slots in the code bars thespring latch 88 rests on the tip of hook 8|.

However, as soon as any one of the code bars B1 to B10 is moved to a newposition by the energization or deenergization of one of theelectromagnets R1 to R10, such a movement of a code bar will force thenon-repeat bar 16 rearwardly .out of the slots in the code bars, therebyfreeing arm 84 from lug 85 and moving the lower hooked end of thenon-repeat bar '|6 inwardly to enable latch 88 to engage hook 8| tothereafter hold the nonrepeat bar out of engagement with the code barsuntil after the cycle of operation is begun again involving theselection of the pull bar 58 illustrated in Figs. 5 to 10. That is, theapparatus of Fig, l0 will be restored to their normal positions of Fig.5 as soon as one of the code bars B1 to B10 has been moved to force thenon-repeat bar out of the slots in the code bars.

Applicants preferred embodiment also includes means for preventing falseprinting by dividing the possible speech sounds into groups and at anyone time preventing the printing of all symbols except thoserepresenting the sounds of one group. Thus, the printing mechanism maybe arranged to determine whether or not a particular setting of the codebars is due to a voiced or an unvoiced sound and if it is due to avoiced sound to automatically lock all pull bars which are associatedwith type bars representing unvoiced sounds.

In the previous description the speech sounds to be printed byappropriate symbols were divided into four groups, namely, voiced orunvoiced stop sounds and voiced or unvoiced non-stop sounds. Theapparatus of Figs. 1 to 10 include means for distinguishing each groupfrom the other three groups and for unlocking the type bars for theparticular group to which each sound belongs.

Eachpull bar 58 for the twenty-four voiced non-stop sounds previouslylisted is of the type disclosed in Figs. 5 to 10 with an upper extension98 comprising two spaced lugs 9| and 92. The armature of electromagnet32 (Fig. 2) has an arcuate-shaped arm 93 which is adjacent to andaligned with the lugs 9| .of all pull bars for the voiced non-stopsounds when the pull bars are in normal position and when electromagnet32 is deenergized. It, therefore, follows that no symbol representing avoiced non-stop sound can be printed as long as electromagnet 32 isdeenergized since as is apparent from Fig. 5 arm 93 will prevent anypull bar for a voiced non-stop sound from testing the code bars.However, when a voiced non-stop sound is received by microphone 28 andwhile the code bars in response to that sound are being set byelectromagnets R1 to R10, electromagnet 32 will also be energized toraise arm 93 to a higher level (Figs. 6 to 10) out of the path of lug 9|when the movement yof main bail 8| permits springs 66 to pull all of thepull bars inwardly to test the code bars. The position of arm 93 whenelectromagnet 32 is energized also serves to lock the pull bars foranother group of sounds as will be described later. The type of controlexercised by electromagnet 34 is similar to electromagnet 32 except thatas long as electromagnet 34 is deenergized no symbol can be printedcorresponding to a stop sound.

In explaining the printing control exercised by electromagnets 32 and 34by reference to Figs. 11 to 14, inclusive, it should be noted from Fig.1 that electromagnet 32 will be operated by al1 voiced non-stop soundsand all voiced stop sounds and will remain unoperated for all unvoicedstop or non-stop sounds; and that electromagnet 34 will be operated byall voiced and unvoiced stop sounds and will remain unoperated for allvoiced and unvoiced non-stop sounds.

The upper portion of a pull bar for one of the twenty-four voicednon-stop sounds is shown in Figs. 12-A to 12D where the pull bar has alug 9| opposite arm 93 for the non-operated position of the armature ofthe voicing lock electromagnet 32 and has a lug 92 opposite the operatedposition of the corresponding arcuate arm 94 connected to the armatureof the stop consonant lock electromagnet 34. In Fig. 12-A bothelectromagnets 32 and 34 are non-operated with arm 93 lying in the pathof lug 9| to prevent a printing operation by any pull bar for a voicednonstop sound. In Fig. 12-B the arm 94 of the stop consonant lock is innormal position but arm 93 of the voice lock is in its operated positionout of the path of lug 9| so that the condition of the controls shown inFig. 12-B will permit the printing of any desired voiced non-stop sound.In Fig. 12-C the voiced lock arm 93 is normal and the stop consonantlock arm 94 is in its operated position from which it is obvious thatpull bar 98 cannot be actuated to cause a printing operation. In Fig.12-D the voiced lock arm 93 is in its operated position and the stopconsonant lock arm 94 is in its operated condition from which it isobvious that the pull bar 99 cannot cause a printing operation due tothe fact that arm 94 lies in the path of lug 92. Therefore, as shown inFig. 12-B the biasing arm 93 must be in its operated position and thestop consonant lock arm 94 must be in its normal position in order tosecure the printing of any character representing one of the twenty-fourvoiced nonstop sounds.

The three pull bars representing the three voiced stop sounds may havetheir upper extensions of the type shown in Figs. l1-A to ll-D where theupper portion 95 of the pull bar has a lug 96 opposite the normalposition of the voiced lock arm 93 and has a lug 91 opposite the normalposition of the stop consonant lock arm 94. An examination of the Figs.ll--A to ll-D will show that the printing corresponding to one of thevoiced stop consonants can be secured only When both arms 93 and 94 arein their operated positions as shown in Fig. ll-D. When arms 93 and 94are in their normal positions as shown in Fig. ll-A no printingoperation can be made because arm 93 lies in the path of lug 96 and arm94 lies in the path of lug 91. When arm 93 is in its operated positionand arm 94 is in its normal position it is apparent from Fig. 11--B thatthere can be no printing operation since arm 94 lies in the path of lug91. When arm 93 is in its normal position and arm 94 is in its operatedposition it is apparent from Fig. 11-C that no printing operation can beeffected since arm 93 lies in the path of lug 96.

The upper portion of a pull bar for one of the three unvoiced stopconsonant sounds may be of the type shown in Figs. 13 A to 13-D Wherethe upper extension |99 of the pull bar has a lug |9| opposite theoperated position of arm 93 and a lug |92 opposite the normal positionof arm 94. It Will be apparent that the printing of a symbolrepresenting one of the unvoiced stop sounds will be permitted When thevoiced lock arm 93 is normal and when the stop consonant lock arm 94 isin its operated position, as shown in Fig. 13--C. When both arms 93 and94 are in their normal positions it will be apparent from Fig. 13-A thatno printing operation Will be permitted since arm 94 lies in the path oflug |92. When arm 93 is in its operated position and arm 94 is in itsnormal position it will be apparent from Fig. 13-B that no printingoperation Will be permitted since arm 93 lies in the path of lug |9| andarm 94 lies in the path of lug |92. When arms 93 and 94 are both intheir operated positions it will be apparent from Fig. 13D that noprinting operation will be permitted since arm 93 lies in the path oflug |91.

The pull bars for the six unvoiced non-stop sounds may each have anupper extension |93 as shown in Figs. 14--A to lll-D, the said extension|93 having a lug |94 opposite the operated position of arm 93 and a lug|95 opposite the operated position of arm 94. It will be apparent fromFig. 14-A that the printing of an unvoiced non-stop sound will bepermitted when both arms 93 and 94 are in their normal positions Wherethey lie out of the path of lugs |94. |95. When the arm 93 is in itsoperated position and arm 94 is in its normal position it Will beapparent from Fig. 14--B that no printing operation will be permittedsince arm 93 lies in the path of lug |94. When arm 93 is in its normalposition and arm 94 is in its operated position it will be apparent fromFig. 14C that no printing operation will be permittedsince arm 94 liesin the path of lug |95. When arms 93 and 94 are both in their operatedpositions it Will be apparent from Fig. l4-D that no printing operationWill be permitted since arm 93 lies in the path of lug |94 and arm 94lies in the path of lug |95.

As a summary of the above description it will be apparent that a voicedstop sound may be printed only when both electromagnets 32 and 34 areenergized (Fig. ll-D); that a voiced nonstop sound can be printed onlywhen electromagnet 32 is energized and electromagnet 34 deenergized(Fig. 12-B); that an unvoiced stop sound can be printed only when theelectromagnet 32 is deenergized and electromagnet 34 energized (Fig.13-C); and that an unvoiced nonstop sound can be printed only when bothelectromagnets 32 and 34 are deenergized (Fig. 14-A).

Various methods may be employed in determining the positions of theslots in the code bars B1 to B10 in order that for a particular soundthe code bars will be moved to align their slots for that sound topermit the printing of the appropriate symbol. Probably the most directway to obtain this information is to determine the average energy levelin each subband for each phonetic sound by connecting a recordingoscillograph to the output of each of the rectiers D1 to D10 so as tomeasure the output current from each rectifier for each phonetic soundspoken into the microphone 29, it being understood that for themeasurement of voiced sounds equalizer 39 is included in the circuit tomake all harmonies of the fundamental frequency of substantially thesame amplitude as the fundamental. With the said equalizer 39 effectivefor voiced but not unvoiced sounds the energy distribution withfrequency of thirty-two of the thirty-six sounds above listed, are givenin the curves of Figs. 3 to 31 of my copending U. S. patent applicationSerial No. 181,275, filed December 23, 1937, where for each curve theloss in decibels is plotted against the frequency. By dividing each ofthese curves into the frequency subbandsI indicated on filters F1 to F10of Fig. 1 and integrating the portion of each curve representing eachsubband the relative amplitude of the output from each rectifier D1 toD10 for each phonetic sound may be readily ascertained. It may befurther assumed that electromagnets R1 to R10 are similar and withsprings 49 similar, and that the attractive force exerted by each ofthese electromagnets on its armature is a linear function of theamplitude of the current received from the associated rectifier. Hence,it may be assumed for the apparatus of Figs. 1 and 2 that the movementof each code bar B1 to B10 from its normal position will be a linearfunction of the amplitude of the output current of its associatedrectifier D1 to D10. However, any other arrangement found desirable maybe used. For instance, the displacements may be made on a logarithmicbasis instead of a linear one. This would be accomplished by a properdesign of the magnetic parts of the electromagnets.

For illustrative purposes the code bars B1 to B10 in Fig. 4 instead ofbeing stacked one upon the other are all shown lying in a common planeso that the relative positions of their slots for certain sounds may bereadily ascertained. Only a small portion of each code bar is shown inFig. 4 and although it is assumed that the printing apparatus of Fig. 2includes thirty-six pull bars, the disclosure in Fig. l includes only vepull bars repeat bar 16E should be so located that they.

since it is believed that these five pull bars will be sucientlyillustrative of the manner of operation of the code bars for all of thethirty-six pull bars contemplated by this invention. In Fig. 4 pull bar50H and associated non-repeat bar 16H control the type bar for the hsound in here; the pull bar 50u and associated non-repeat bar 16ucontrol the type bar for the boldfaced sound in the word cool; the pullbar 50s and associated non-lepeat bar 16s control the type bar for the ssound in seal; the pull bar 50E and associated non-repeat bar 16Econtrol the type bar for the e sound in well; and the pull bar 50T andassociated non-repeat bar 16T control the type bar for the unvoiced stopconsonant t. All of the code bars are assumed to be in their normalpositions' with each code bar being moved to the left as viewed in Fig.4 by its associated electromagnet in accordance with the amplitude ofthe current from each rectifier D1 to D10 for each phonetic sound. Theslots in code bars B1 to B10 which must be aligned by the propermovement of each code bar before pull bar 50H can enter the code barsare designated H1 to H10, inclusive, and the corresponding slots for theassociated non-repeat bar 16H are designated H1 to H10; the slots in thecode bars which must be aligned for the entrance of pull bar 50c andnon-repeat bar 16u are designated respectively U1 to U10 and U1 to U10;the corresponding slots for pull bar 50s and non-repeat bar 16s aredesignated S1 to S10 and S'i to S10; the corresponding slots for pullbar 50E and non-repeat bar 16E are designated E1 to E10 and E1 to E10;and the corresponding slots for pull bar 50T and non-repeat bai 16T aredesignated T1 to T10 and T1 t0 Tio.

An examination of the curves of Figs. 4, 11, 12, 23 and 25 of myabove-mentioned copending application when integrated over each subbandfor the :live sounds whose pull bars are shown on Fig. 4 will show thatthe relative energy values for the various subbands are such that theten code bars in response to these five sounds will be moved distancesproportional to the integers given in the following table if wearbitrarily assign the value of sixteen units of distance as the maximumdistance any code bar will be moved for any subband of the designatedfive sounds:

Thus if we assume for the s sound in seal that each of the code bars B9and B10 moves 1%4 of an inch, then code bar Bs will move $454 of aninch, code bar B1 will move %4 of an inch, code bar B will move 1,61 ofan inch, while there will be no appreciable movement of code bars B1 toB5; and hence slots S1 to S10 for pull bar 50s and vslots S1 to S10 fornon-repeat bar 16s should be so located that they will be aligned whenmoved the distances just specified. On a similar assumption for the esound in well, code bars B2, B3, B1, B7, B3 will each be moved 1,(,4 ofan inch, code bar B0 will be moved 4@ of an inch, while there will be noappreciable movement for code bars B1, B5, B0 and B10; and hence slotsE1 to E for pull bar 50E and slots E1 to E10 for nonwill be aligned whenmoved the distances just specified. On a similar assumption for the tsound in ten there will be no appreciable movement of code bars B1 toB7, inclusive, while code bar Ba will move %.1 of an inch, code bar B9will move 1%.; of an inch, and B10 will move F764 of an inch; and henceslots T1 to T10 for pull bar 501* and slots T1 to T10 for non-repeat bar76T should be so located that they will be aligned when moved thedistances just specified. It will be apparent from the examples justcited how one should locate the corresponding slots in the code bars forthe other thirty-three sounds' listed in the earlier part of thisspecication.

A few comments may be noted as to the general character of the slots inthe code bars for receiving the pull bars and the non-repeat bars. Thewidth of each pull bar slot with respect to the width of a pull bar willbe determined by how much tolerance should be allowed for possiblevariations in the movement of any code bar in response to the samephonetic sound. In Fig. 4 it may be assumed that the mouth of each pullbar slot is about twice the width of each pull bar. Each pull bar slotshould have fairly ste'ep side walls. However, for the non-repeat barsthe slots should be relatively shallow with gradual sloping side wallsin order to reduce the force required to move one of the non-repeat barsout of the slots for each new alignment of the code bars. In locatingthe ten slots in the code bars for each of the thirty-six phoneticsounds, suitable precautions must be taken in their location along thecode bars whereby when the ten slots for any one sound are aligned nocorresponding alignment will occur for the ten slots for any other pullbar. This should not present any difficulty as is brought out by theconsideration of the phonetic nature of speech and the large number ofpossible selections available. Ii we assume we can get ten recognizablesteps in energy level in each of the ten frequency bands then we have atotal of ten billion recognizable phonetic elements as against onlythirty-six needed. Furthermore, the nature of speech is such that thesethirty-six sounds diier from one another as much as possible. The stepsprovided in the present application provide for a far greater selectionthan is needed. This excess may be used advantageously in several ways.Some sounds are spoken a little differently from section to section ofthe country and by people differing in age, sex, culture, etc.Variations of this nature can be allowed for so that all possibleselections are available, that is, a greater degree of selection may beutilized. Again, for certain sounds it may be desirable to have severalforms recognized, making the total more than thirtysix but having two ormore type bars print the same sound. For example, various pronunciationsof r might be thus provided for or the various pronounced forms might beprinted separately where this information was desired. With such a largenumber of selections available further modifications of the mechanismmay be made to stress the differences between sounds which are commonlymisunderstood, such as f and th.

A large amount of the extra selectivity avail* able over what is neededwill be taken up in designing ior smoother operation of the pull bars intesting on the code bars. As the pull bars come in to test, either allwill fail to enter sunlciently for typing operation or all but one willfail to enter. The pull bars that fail to enter will be stopped byhaving some part of the pull bar strike a single code bar, the firstcode bar encountered by the pull bar. The pull bar that enters the codebars goes all the way in until stopped by the stationary cam 12 as inFig. '7, so that it does not contact with any code bar. The rejectedpull bars in contacting the code bars will offer some resistance to themotion of the code bars. This will not be serious, however, because ofthe fewness of these contacts, because each contact period is of shortduration, and finally because the code bars are moving at slow syllabicrates so that the amount of travel is small during the normal contactingperiod. However, consideration should be given to the mechanical designof the pull bars and the code bars to insure smooth operation. In thefirst place the pull bars may be permitted to bounce back slightly aftercontact with the code bars. In the second place a slight amount ofbending in a rejected pull bar may be permitted when the pull barcontacts with the code bars. It may also be desirable to provide roundededges at the contacting points between the code bars and the pull barsand provide for a minimum friction at such points by having smoothsurfaces with lubrication by an oil film or graphite or special metalsurfaces as needed.

In the mechanism disclosed in Fig, 2 it is assumed that the successiveactuation of the thirtysix type bars 62 will print their symbols upon anelongated strip of paper carried by the platen 1|. The main bail plunger60 has an indent 5| for receiving a roller |52 carried by the spacingoperating lever |53. Roller |52 is held against indent |5| by spring |54so as to ride into and out of indent |5| as the plunger 60 moves up anddown. Attached to the lower part of lever |53 is the spacing feed pawl|55 which is constantly forced into engagement with the teeth of thespacing ratchet wheel |56 by spring |51. Ratchet wheel |56 is mountedupon shaft |58, geared to the platen shaft |59 by gears |60, |6|.Mounted upon shaft |58 is the platen wheel 1| which cooperates with afeed roller |62 held against platen 1| under pressure by spring |63 forspacing or feeding the message tape (not shown) one letter space at atime for each movement of plunger 60. The above-described manner ofcontrolling rotatable platen 1| is disclosed more fully in the Lang etal. U. S. Patent 2,106,805.

The above-described arrangement for moving platen 1| one step for eachupward excursion of plunger 60 will mean that' occasionally there willbe gaps between the symbols representing a single spoken word andoccasionally there may be no blank space between the last symbol for oneword and the rst symbol of the succeeding word but such irregularitieswill not interfere with the intelligibility of the printed message. Itwill, in fact, correspond to the usual condition of hearing of speechsounds. However, if desired, the apparatus may be arranged to have themessage tape advanced only after a symbol is printed.

The preferred form of this invention not only prints phonetic symbols onthe message tape corresponding to the speech sounds received bymicrophone 20 but also registers on the tape the volume and pitch of thespoken sounds. It will be noted that the output from microphone 20 isalso supplied to a branch circuit |68 leading to an amplifier |69, anetwork |10 and rectifier I1| with the output current of rectifier |1|by conductors |12 supplied to an electromagnet |13. Network |10 isdesigned to give a proper loudness weighting for different frequenciesso that the output current from rectifier 1| will be a measure of theloudness of the speech sounds received by microphone 20, whereby theamplitude of the rectified current from rectier |1| will increase withincrease in the volume of the sound. The Weighting of differentfrequencies for loudness contribution may be taken from Fig. 109 of abook by Harvey Fletcher on Speech and Hearing published in 1929 by VanNostrand. As shown in Fig. 2, the platen assembly has a variableprinting position determined by the volume indicator electromagnet |13.The a1'- mature of electromagnet |13 is coupled to an extension |14 ofthe platen assembly and the printing position of platen 1| withelectromagnet |13 deenergized is determined by the biasing spring |15which pulls extension |14 and platen 1| rearwardly until adjustablescrew |15 contacts with stop |11. However, the electromagnet |13 inattracting its armature moves the platen assembly forwardly an amountdependent upon the loudness of the speech received by microphone 20, andhence the symbols typed on the tape |86 (Fig. 3) carried by platen 1|will not be along a horizontal line but the printing line |81 will havean upward slope if the spoken sounds are of increasing loudness and willhave a downward slope if the sounds are of decreasing loudness. Thus ifthe phrase This is phonetic printing is spoken into microphone 20 withvariable loudness, the record when printed in symbols of theInternational Phonetic Alphabet may be that shown in Fig. 3 for the caseof operating at full speed.

Referring back to Fig. 1 itl has already been pointed out that theamplitude of the output current from filter 24 is proportional tothepitch of the fundamental frequency of each voiced sound. Electromagnet'|56 is connected across the output terminals of filter 24 and hence theforce exerted by electromagnet |56 on its armature |61 is proportionalto the pitch of each voiced sound. As shown in Fig. 2 electromagnet |66is mounted on the platen 10 and is movable therewith. The armature ofelectromagnet |66 is coupled to one arm of a lever pivoted about pin |8|on. the platen assembly and biased by spring |82 to a positiondetermined by stop screw |83. Pivoted to lever |80 is an arm |84carrying a pen or pencil |85 for tracing a line on the message tapecarried by platen 1|. The relative position of the trace |88 made by pen|85 on the message tape |86 is, therefore, controlled by electromagnet|66 and hence an increase in the pitch of the voiced sounds received bymicrophone 20 will cause pen |85 to trace a line having an upward slopewhile a decrease in the pitch of the voiced sounds will give the tracedline a downward slope. It' is, therefore, apparent that due toelectromagnets |66 and |13 with their associated apparatus, the messagetape on platen 1| will carry a record not only of the symbolsrepresenting the spoken sounds but also a record of variations in theloudness and pitch of the talker.

Channel 23 of Fig. 1 will now be briefly explained whereby the currentoutput of lter 24 has an amplitude proportional to the pitch of thefundamental frequency of the voiced sounds. Band-pass filter |90 selectsthe band from 50 cycles to 500 cycles per second of the speech currentsso as to be sure to include two harmonics 75 of the fundamentalfrequency for any voiced sound of low pitch and the fundamentalfrequency of any voiced sound of high pitch. The frequencies passed byfilter |90 are passed through a fundamental frequency discriminatingcircuit ISI which has a loss increasing with the frequency for thepurpose of insuring that the fundamental frequency comes out at a higherlevel than any harmonic thereof that may be present. For practicalpurposes this puries the fundamental tone. Next, the output fromequalizer i9! is fed to a frequency meter |92 which may be similar tothat described in the copending application of R. R. Riesz, Serial No.100,291, filed September 11, 1936. The fundamental frequency may be anyfundamental frequency of speech, say, between 50 cycles and 500 cyclesper second. As described in the Riesz application the output of thefrequency meter |92 comprises a number of pulses of substantiallyuniform size, there being one such pulse for each cycle of thefundamental frequency which varies at a syllabic frequency rate. Theoutput from frequency meter |92 is then sent through the lowpass lter 24cutting off at 20 cycles per second, so that the unwanted frequencycomponents are eliminated.

There remains to be discussed the frequency of operation of the mainbail 6|. Tests have indicated that a moderate rate of talking will giveabout 400 phonetic letters per minute which means an actuation of typebars 62 at the rate of about 400 per minute. This compares favorablywith teletypewriter operation where speeds as high as 600 characters perminute have been obtained in page printing and about twice this rate fortape printing. Part of the mechanism of Fig. 2 must operate faster thanthe actual typing rate on the message tape. The apparatus of Fig. 2 isset up to test the code bars at fixed intervals of time and these timeintervals should be short enough that the shortest speech sound will beexamined and recorded. Tests indicate that the fastest talker speakingintelligibly cannot say more than 1500 sounds a minute. If we assumethat the pull bars should be operated, say, twice per sound at this highspeed with correspondingly increased testing at lower speeds then themain bail 6| should be operated at the rate of about 3000 operations perminute with the type bars working at a maximum of about 1500 perminute.1

While the apparatus of Figs. 1 and 2 has been disclosed with specialauxiliary devices such as a non-repeat bar, a voicing lock electromagnet32, a stop consonant lock electromagnet 34, a pitch indicatorelectromagnet |66, and a volume indicator electromagnet |13 it is to beunderstood that one or more of these devices may be omitted if desired.In particular all of the apparatus of Fig. 1 surrounded by dotted line200 may be omitted, in which event the output terminals of vogad 2| maybe connected directly to the input terminals of the parallel connectedfilters F1 to F10. In the case of a reasonably constant calling levelthe vogad 2| may be omitted entirely or replaced with a potentiometerwhich the talker can adjust to his calling level as he starts to talk.While the volume indicator and the pitch indicator have been arranged tomake certain types of records on the message tape it is obvious thatelectromagnets |66 and |13 may control the record in various other waysto produce indications of variations in the volume and pitch of thespoken sounds. It has been convenient to disclose printing the phoneticsymbols on a message tape but the invention is not so limited as pageprinting may also be employed if desired. While applicant has preferredto divide the speed frequency band into ten subbands of frequency rangesindicated by lters F1 to F1o it is to be understood that the frequencyrange of importance in speech may be divided into a greater or a smallernumber of channels with substantial modifications of the bandtransmitted through each channel over the frequencies designated inFig. 1. For example, in the case of typing a message received over atypical telephone line passing from 250 to 3000 cycles per second thelowest frequency band and the three highest frequency bands into whichthe speech range is divided by the band-pass filters of Fig. 1 wouldcontain essentially no energy so that these bands could be omitted; andfor such use it would be desirable to still divide the speech range from250 cycles to 3000 cycles per second into ten subbands differingsubstantially from those illustrated in the circuit of Fig. 1.

While this invention has been disclosed as applied to message tapeprinting it will be obvious that the invention may be utilized with pageprinting apparatus. It may also be desirable for certain purposes tohave the message tape fed forward each time a symbol is printed ratherthan each time the main bail is moved upwardly.

It will also be understood that this invention may be used in connectionwith the printing of sounds other than speech sounds such as theprinting of symbols representing music either vocal or instrumental.

What is claimed is:

1. A sound printing system comprising a transmitter for transformingvocal sounds into electrical waves, means for amplifying said waves to avarying degree to compensate for any slow variations in the loudness ofthe sounds reaching said transmitter whereby a relatively constantvolume is lattained from the output of said amplifying means, means fordividing the amplified waves` into a plurality of subbands of frequency,and printing mechanism selectively controlled by the average energylevel in the various subbands. A

2. A sound printing system comprising a transmitter for transformingvocal sounds into electrical waves, means for amplifying said waves to avarying degree to compensate for any slow variations in the loudness ofthe sounds reaching said transmitter whereby a relatively constantvolume is attained from the output of said amplifying means, means fordividing the amplified waves into a plurality of subbands of frequency,a plurality of movable elements one for each frequency subband, each ofsald elements being biased to a definite position, means for moving eachof said elements to any one of a plurality of advanced positions inaccordance with the average energy level in one of said subbands foreach voiced sound, and printing mechanism selectively controlled by saidlast means.

3. Apparatus for translating spoken sounds into printed words comprisinga transmitter for transforming said sounds into electrical waves, anequalizer network for subjecting said waves to a transmission loss whichdecreases with frequency to compensate for the relatively low amplitudeof the upper harmonics of the fundamental frequency of a voiced sound,means for transmitting said waves through said network when said wavesrepresent a voiced sound while rendering said network ineffective whensaid waves represent an unvoiced sound, means for dividing said wavesinto a plurality of subbands of frequency and printing mechanismselectively controlled by the average energy level in the varioussubbands.

4. A sound printing system comprising a transmitter for transformingvocal sounds into electrical waves, means for amplifying said waves tocause said waves to have a substantially constant energy level forsuccessively spoken words to compensate for any variations in theloudness of-the talker, means for` dividing said waves into a pluralityof subbands of frequency, printing mechanism comprising a plurality oftype bars, a control bar individual to each type bar, certain of saidcontrol bars corresponding to voiced sounds and other control barscorresponding to unvoiced sounds, means for selectively actuating saidcontrol bars one at a time in an order determined by the relative energylevels in said frequency subbands for the successively spoken sounds,and means effective when said waves represent an unvoiced sound forpreventing the actuation of any of said certain bars.

5. A sound printing system comprising a transmitter for transformingvocal sounds into electrical waves, means for amplifying said waves tohave a substantially constant energy level for successively spoken wordstocompensate for any variations in the loudness of the talker, means fordividing said amplified waves into a plurality of subbands of frequency,printing mechanism comprising a plurality of type bars, certain of saidtype b-ars being for voiced sounds, other of said type bars being forunvoiced sounds, means for selectively actuating said type bars inaccordance with the relative energy levels in said frequency subbands,and means effective when the waves impressed upon said amplifying meansrepresent an unvoiced sound for preventing the accidental actuation ofone of said certain bars.

6. A sound printing system comprising a transmitter for transformingphonated sounds into electrical waves, means for dividing said Wavesinto a` plurality of subbands of frequency printing mechanism comprisinga plurality of type bars, certain of said type bars representing soundshaving a discrete frequency spectrum, other of said type barsrepresenting sounds having a substantially continuous frequencyspectrum, means for selectively actuating said bars in accordance withthe relative energy levels in said frequency subbands, meansy normallylocking said certain bars, and means responsive to a sound wave having adiscrete frequency spectrum for unlocking said certain bars.

'7. A sound printing syst-em comprising a transmitter for transformingspeech sounds into electrical waves, means for dividing said waves intoa plurality of subbands of frequency, printing mechanism comprising aplurality of type bars, certain of said bars representing stop consonantsounds, other of said bars representing other types of sounds, means forselectively actuating said bars in accordance with the relative energylevels in said frequency subbands, means normally locking said certainbars, and means responsive to a stop consonant sound received by saidtransmitter for unlocking said certain bars.

8. Apparatus for rtranslating spoken sounds into printed wordscomprising a transmitter for transforming said sounds into electricalwaves, means for dividing said waves into a plurality of subbands offrequency, aplurality of movable code bars one for each subband, meansfor actuating each code bar in accordance with the average energy levelin one of Vsaid subbands whereby said code bars for each actuationassume relative positions which collectively define the sound initiatingtheir actuation, a plurality of type bars each representing a differentvoiced or unvoiced sound, and means for testing said code bars in theiradvanced positions to select a type bar representing the sound definedby the relative positions of said code bars and for causing a printingoperation by the selected type bar.

9. Apparatus for translating into printed symbols a complex electricalwave representing phonated sounds having not more than one fundamentalfrequency at any given instant, comprising means for selecting a numberof substantially independent characteristics of said wave, a pluralityof movable code bars each controlled in position by the syllabicvariations of one of said characteristics whereby for each portion ofsaid wave representing a separate sound said code bars assume positionscollectively defining said sound, and printing mechanism selectivelycontrolled by said code bars.

10. Apparatus for translating a complex electrical wave representingspeech into printed words comprising means for selecting a set ofsubstantially independent parameters corresponding in number to thenumber of the important independently movable elements of the vocalsystem involved in speech production, means for assigning to each ofsaid parameters a value independently controlled by the syllabic rate ofchange of an essential characteristic of said wave, a plurality ofmovable code bars each biased to a definite normal position and adaptedto be moved to any one of a plurality of advanced positions, each ofsaid bars being controlled in position by the value of a different oneof said parameters for each speech sound, and printing mechanismselectively controlled by said code bars.

11. Apparatus for translating a complex electrical wave representingspeech into printed words comprising means for amplifying said wave tocause the wave to have a substantially constant energy level forsuccessively spoken words to compensate for variations in the loudnessof the talker, means for selecting a set of substantially independentparameters corresponding in number to the number of the importantindependently movable elements of the vocal system involved in speechproduction, means for assigning to each of said parameters a valueindependently controlled by the syllabic rate of change of an essentialcharacteristic of said amplified wave, and printing mechanismselectively controlled by the syllabic variations in the values of saidparameters.

12. Apparatus for translating into printed symbols an electrical waverepresenting phonated sounds comprising means for dividing said waveinto a plurality of frequency subbands, means for rectifying the energyin each subband, Ia plurality of movable code bars one for eachfrequency subband, each of said bars being biased to a normal position,means for actuating each of said code bars to any one 'of a plurality ofadvanced positions in accordance with the rectified current from adifferent oneof said subbands whereby the extent to which each bar isadvanced is a measure of the amount of power in the frequency subband,and printing mechanism selectively controlled by said code bars.

13. Apparatus for translating into printed words a complex electricalwave of a wide band of frequencies representing speech, comprising meansfor dividing said wave into a plurality of frequency subbands, means forrectifying the energy in each subband, a printing bail, a plurality ofpull bars adapted to be operated by the printing bail, a plurality ofcode bars whose relative positions at any given instant define whichpull bar will be actuated by said bail, each code bar being biased to anormal position and adapted to be advanced to any one of a plurality ofadvanced positions, and means for advancing each code bar to that one ofits possible advanced positions which defines the relative amplitude ofthe rectified current from a different one of said subbands.

14. Apparatus for translating into printed Words a complex electricalwave of a Wide band of frequencies representing speech, comprising meansfor dividing said wave into a plurality of frequency subbands, means forrectifying the energy in each subband, a printing bail, a plurality ofpull bars adapted to be operated by the printing bail, a plurality ofcode bars for selecting the particular pull bar to be operated at agiven instant, means for setting each of said code bars in accordancewith the amplitude of the rectified current from a different one of saidsubbands, certain of said pull bars representing a voiced sound, othersof said pull bars representing an unvoiced sound, means for locking saidcertain pull bars against accidental operation by said bail when theparticular setting of said code bars defines an unvoiced sound, andmeans controlled by the voiced portions of said complex wave forvreleasing said locking means.

15. Apparatus for translating into printed words a complex electricalwave of a wide band of frequencies representing speech sounds, saidapparatus comprising means for dividing said wave into a plurality offrequency subbands, a plurality of selectors, means for shifting eachselector in accordance with the average energy level in one of saidsubbands whereby said selectors assume certain relative positions forthat portion of said Wave representing one speech sound and assumedifferent relative positions for that portion of said wave representingthe succeeding speech sound, a plurality of type bars, one representingsaid first speech sound, means responsive to the shifting of saidselectors to said certain positions for actuating said one bar, andmeans for preventing a second actuation of said one bar during the timeinterval said selectors remain stationary in said certain relativepositions.

16. Apparatus for translating into printed words a complex electricalwave representing speech sounds comprising a plurality of selectors,means for shifting said selectors to certain relative positions definingthat portion of said wave representing said one speech sound and forsubsequently shifting said selectors to different relative positionsdefining that portion of said wave representing the next succeedingspeech sound, a plurality of type bars one of which represents saidfirst speech sound, means responsive vto the arrival of said selectorsto said certain positions for actuating said one type bar, and means forpreventing a second actuation of said one bar during the time intervalsaid selectors remain stationary in said certain relative positionsbefore assuming different relative positions.

17. Apparatus for translating into printed words a complex electricalwave representing speech sounds, comprising a plurality of selectors,means for controlling said selectors in accordance with the portion ofsaid wave representing each speech sound, a plurality of type bars, arecord sheet, means controlled by said selectors for selectivelyactuating said type bars to strike said sheet, and means for indicatingon said sheet variations in the pitch of those portions of said Waverepresenting voiced speech sounds.

18, Apparatus for translating into printed words a complex electricalwave representing speech sounds, comprising a plurality of selectors,means for controlling said selectors in accordance with the portion ofsaid wave representing each speech sound, a plurality of type bars, arecord sheet, means controlled by said selectors for selectivelyactuating said type bars to strike said sheet, and means for indicatingon said sheet variations in said wave representing variations in therelative loudness of the speech sounds.

19. Apparatus for translating into printed symbols a complex electricalwave representing speech sounds comprising means for modifying theportions of said Wave representing voiced sounds to increase theamplitude of the harmonic frequencies relative to the amplitude of thefundamental frequency, a set of selectors, electrical means responsiveto the modified voice portions of said wave and to the unmodifiedunvoiced portions of said wave for controlling said selectors to assumesuccessive conditions dening the various speech sounds, a plurality oftype bars and means controlled by said selectors for selectivelyactuating said type bars.

20. Apparatus for translating into printed words a complex electricalwave representing a succession of spoken words uttered with a varyingdegree of loudness, said apparatus comprising means for amplifying saidwave to cause that portion of said wave representing one word to havesubstantially the same energy level as other portions of said waverepresenting other words, a set of selectors, electrical meansresponsive to the amplified wave for controlling said selectors toassume successive conditions defining the various speech sounds, aplurality of type bars, and means controlled by said selectors forselectively actuating said type bars.

21. Apparatus for translatin into printed words a complex electricalwave representing speech sounds, a set of selectors, means for shiftingsaid selectors to positions defining that portion of said waverepresenting a certain unvoiced sound, a plurality of type bars onerepresenting said unvoiced sound, a second type bar representing avoiced sound, means responsive to said shifting of said selectors tocause a printing operation by said one type bar and means for preventinga printing operation by said second bar while said selectors occupy saidshifted positions defining said certain unvoiced sound.

22. Apparatus for translating into printed words a complex electricalwave representing speech sounds comprising means for amplifying saidwave to a varying degree to compensate for difference in the energylevels of portions of said wave representing different words, anelectrical network having a loss decreasing with increase in frequency,means for causing voiced portions of said wave to traverse said networkand for causing unvoiced portions to by-pass said network, a set ofselectors, electrical means for controlling said selectors, means forcontrolling said electrical means in accordance with the output of saidnetwork for voiced sounds and in accordance with the unvoiced portionsof said wave bypassing said network whereby said selectors aresuccessively conditioned to collectively dene each different speechsound represented by said wave, and printing mechanism selectivelycontrolled by said selectors.

23. Apparatus for translating into printed words a complex electricalwave representing speech sounds, said apparatus comprising a pluralityof notched code bars, means for selectively shifting said bars to causesaid bars to successively assume positions collectively dening eachdiierent speech sound represented by said Wave, a plurality of typebars, an actuating lever individual to each type bar and movable intoand out of engagement with said code bars, and means for periodicallymoving al1 of said levers into engagement with said code bars and forcausing a printing operation by any type bar whose actuating leverenters the notches in said code bars.

24. Apparatus for translating into printed words a complex electricalwave representing speech sounds, comprising a plurality of code barscontaining spaced notches on corresponding surfaces of each bar, aseries of spaced test bars one for each phonetic sound to be printed,means for periodically urging said test bars towards the notchedsurfaces of said code bars, means responsive to the portion of said waverepresenting each speech sound for selectively actuating said code barsto align a notch in each code bar to permit the entrance into thealigned notches of that test bar representing the sound defined by theparticular alignment of the notches, and printing means controlled bythe entrance of any test bar in said notches.

25. Apparatus for translating into printed words a complex electricalWave representing speech sounds, said apparatus comprising a pluralityof code bars containing spaced notches on corresponding surfaces of eachbar, a series of spaced test bars one for each phonetic sound to beprinted, means for periodically urging said test bars towards saidnotched surfaces and for subsequently withdrawing said test bars, meansresponsive to the portion of said wave representing each speech soundfor selectively actuating said code bars to align the notches in saidcode bars to permit the entrance into the aligned notches of that onetest bar representing the sound defined by the particular alignment ofthe notches, printing means controlled by the entrance of any test barin the aligned notches, and means effective for the duration of saidparticular alignment of said code bars for preventing a second entranceof said one test bar into said notches.

HOMER W. DUDLEY.

